The invention relates to a device for milling grooves into boards which are to be pronged together at right angles for comb-like wedge joints by a milling cutter hand machine, with on the side of a workbench a right-angled gauge including a supporting plate and a back plate, and with--on the side of the milling cutter--a guiding piece, wherein both plates of the gauge are provided with slits in a comb-like way, the slits passing in alignment into one another in the reach of the corner edge of the gauge, and wherein the guiding piece is adapted to be guided by the slits of the gauge.
In the production of wooden furniture, bureau drawers, cases or the like, it is generally customary to assemble two boards abutting with their ends against each other at a right angle by a so-called wedge joint. For this purpose, several grooves are milled into the ends of each board, whereby the wedges developed between two adjacent grooves, must provide a cross-sectional shape which is congruent with the grooves. In the case of one of these boards, namely the so-called "cross-bar", the grooves must be oriented perpendiculary in relation to the plane of the board, while in the case of the other board, namely, the so called "longitudinal board", the run is parallel to its main surfaces. Further, the grooves and wedges in the case of one of the board must be displaced in a completely exact manner by always one half of the middle groove distance in relation to the grooves and wedges of the other board, so that the wedges of one board will fit into the respective grooves of the other board.
In West German Pat. No. 2,642,924, corresponding to U.S. Pat. No. 4,074,736, wedge joints of the aforementioned are milled by a hand operated milling cutter machine which includes on the side of a workbench of a right-angled gauge with a supporting plate and a back plate. Both plates are provided in a comb-like manner with slits passing in alignment into each other in an area of the corner edge of the plates. A guiding member, or the side of the milling cutter machine is guided in the slits of the gauge. By this milling cutter machine, it is possible to mill grooves into the cross bar and the longitudinal bar with the necessary precision of the relative position without extensive calculation and measuring; however the board, manufactured in a second place, must be clamped together with the gauge in such a way that it is displaced by exactly one half of the middle groove distance, if the two boards are to be assembled with flush edges. This clamping of the second board still needs certain aligning efforts and does not exclude the possibility of incorrectnesses.
The aim or object underlying the present invention essentially resides in providing a milling device for ensuring a correct alignment of the second board in a fool-proof manner.
A further object of the present invention resides in providing a milling device for an exact manufacturing of wedge joints of boards with flush edges or displaced edges as well.
Another object of the present invention resides in providing a milling device for manufacturing exact wedge joints for small boards or large boards.
A still further object of the present invention resides in providing a milling device adapted to mill dovetail grooves or rectangular grooves.
In accordance with advantageous features of the invention, the supporting plate of the gauge is provided at a free edge thereof, opposite to a corner edge of the plates, with at least one projecting aligning finger which is staggered with respect to said slits so that it is aligned with a prong remaining between two of the slits, whereat the cross-section of the aligning finger is adapted to the outline of the grooves which are to be milled.
As a result of achieving the object of the invention, a number of advantages will be achieved. First, the grooves of the longitudinal bar can be manufactured by the milling device in a conventional way. Then, this first board is turned upside down and put with its groove side and with flush edges, or, if desired with displaced edges, on the second board. The alignment of the gauge for milling the transverse grooves of the second board is now achieved by introducing the alignment finger into a groove of the first board. In this way, the exact relative positioning of grooves and wedges of the two boards is achieved without time consuming measuring and complicated aligning efforts and with regard to the desired relative position of the edges of the boards.
According to a preferred embodiment of the invention, the two aligning fingers are arranged in the middle of the supporting plate, the distance between the center lines thereof being equal to the distance between the center lines of the adjacent slits.